Rc1: Cleaned jpg increased file size.

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Taboc

Rc1: Cleaned jpg increased file size.

Post by Taboc »

Some jpg increase file size when Clean:Optimize huffman table is unchecked.

http://img64.imageshack.us/img64/3416/13kz1.jpg
http://img64.imageshack.us/img64/7514/22ju1.jpg

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Xyzzy
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Post by Xyzzy »

Yes, there is something wrong about Clean.

Files with no EXIF/IPTC data grow after they are cleaned with EXIF/IPTC related options checked.

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xnview
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Re: Rc1: Cleaned jpg increased file size.

Post by xnview »

Taboc wrote:Some jpg increase file size when Clean:Optimize huffman table is unchecked.
Seems to be correct :-) All other software with a clean feature have this behaviour...
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Re: Rc1: Cleaned jpg increased file size.

Post by Dreamer »

xnview wrote:
Taboc wrote:Some jpg increase file size when Clean:Optimize huffman table is unchecked.
Seems to be correct :-) All other software with a clean feature have this behaviour...
So close?
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Clo
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Not always…

Post by Clo »

:) Hello !
Seems to be correct All other softwares with a clean feature have this behaviour…
… that doesn't mean it's normal and logical…

- I tested with the image below, and got a small gain at size, ~4KB less…

—————Image

- Please, could you check whether you get the same ?
{ BTW : the caption on the pic tells «I've also MY anti-virus ;) }

:mrgreen: Kind regards,
Claude'
Clo
Last edited by Clo on Sun Jan 15, 2006 12:51 am, edited 1 time in total.
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FlorianH
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Re: Not always…

Post by FlorianH »

Clo wrote:- Please, could you check whether you get the same ?
I can confirm:

a) original file 58.191 bytes
b) original file cleaned with all options except optimize -> 58.191 bytes (same size)
c) original file cleaned with all options (incl. optimize) -> 54.259 bytes
d) file c) cleaned with all options except optimize -> 58.191 bytes strange!

I think from the technical point of view (pierre's view?), behaviour b) is ok. But behaviour d) is not realy easy to explain...
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Post by Dreamer »

Moved back to New/Open, since it's still not clear if current behavior is standard or not.
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Post by xnview »

Dreamer wrote:Moved back to New/Open, since it's still not clear if current behavior is standard or not.
There is no bug here :-)
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Olivier_G
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Post by Olivier_G »

Seems strange that removing data actually increase filesize... :(
-> can't you actually remove the corresponding metadata space completely ?
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Post by xnview »

Olivier_G wrote:Seems strange that removing data actually increase filesize... :(
-> can't you actually remove the corresponding metadata space completely ?
Metadata is removed, but i think that huffmann code is rearranged.
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Post by Xyzzy »

xnview wrote:
Olivier_G wrote:Seems strange that removing data actually increase filesize... :(
-> can't you actually remove the corresponding metadata space completely ?
Metadata is removed, but i think that huffmann code is rearranged.
OK, I think this solves the puzzle. But is there any need to NOT optimize Huffman tree?

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Olivier_G
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Post by Olivier_G »

More tests:
I converted a TIFF to JPEG (no Huff Optimization) -> image without metadata: 323644 B
I added several IPTC&Comments -> 323977 B
I cleaned those metadata (no Huff Optimize) -> 323644 B
=> back to original size without metadata (optimize Huff gives 320305 B).

It looks fine to me regarding the way metadata are handled.
(and also regarding Huffman table optimization)

Olivier
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Post by Xyzzy »

Xyzzy wrote: OK, I think this solves the puzzle. But is there any need to NOT optimize Huffman tree?
Self-reply :)

Yes, when there is image with already optimized coding (fe. by some specialized packer)- applying Huffman could grow it. Looking at Olivier_G test it can be Closed, right?

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